[badpun]

> We keep moving parts isolated because the fewer "things" that something does, the less likely it is to break. The less complicated it is.

It doesn't really work if I'm breaking up a function body into a bunch of smaller functions that will never be called from anywhere except the refactored function. I've just moved the complexity from a large function body into a bunch of smaller functions and the calls to them - but it's still the exact same logic, with the same complexity (but perhaps harder to read, due to all the jumping back and forth).